Butterflies and Moths (Lepidoptera) – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

October 4, 2025

With temperatures finally climbing to seasonable levels and with stormy sun filtering through the yellow-brown smoke coming our way courtesy of wildfires in Alberta and other parts of central Canada, we ventured out to see what might be basking in our local star’s refracted rays…

Dragonflies including this Black Saddlebags are now actively patrolling the edges of waterways and wetlands for prey and mates.

Here we see a pair of Common Green Darners flying in tandem…

A sunny day almost always brings out the reptiles, including these Painted Turtles…

and the invasive Red-eared Slider, a native transplant from the American midwest.

A really big Snapping Turtle will prey on almost anything, including other Snapping Turtles…

…but this one seems to be fascinated by something a lot smaller. Something like these juvenile Golden Shiners seen here schooling in the sun-drenched shallows.

Turtles aren’t the only reptiles thriving in the heat. Northern Water Snakes (Nerodia sipedon sipedon) take full advantage of a sun-drenched rock to warm up after spending time in the chilly water of a stream.

Butterflies like this Spicebush Swallowtail enjoy time in the sun, even while seeking out minerals in a patch of moist soil.

Woodchucks — After its siblings darted into the familial burrow upon our approach, this juvenile Woodchuck instead sought the attention of its nurturing mother. Unlike its brothers and sisters, perhaps this little groundhog isn’t afraid of its own shadow. Or does the smoky haze have the youngster all confused about what does and doesn’t constitute as a shadow? Well, we can’t help you there, but you have a whole eight months to figure it out!

May 25, 2025May 25, 2025

Late May Action in the Forest

Here’s a short preview of some of the finds you can expect during an outing in the Lower Susquehanna River Watershed’s forests this week…

The Mountain Laurel, designated as Pennsylvania’s state flower, is now in bloom.

Mountain Laurel Flower Buds — The buds of the Mountain Laurel remind us of a sugary frosting freshly squeezed from a baker’s pastry bag.

Mountain Laurel Flowers — The flowers of the Mountain Laurel, an evergreen understory shrub, invite pollinators to stop by for a sweet treat.

Little Wood-Satyrs (Megisto cymela) are patrolling forest edges looking for mates and, to host their eggs and larvae, the stands of grasses they find most suitable.

Many of the species of small butterflies we call skippers are now active. The Zabulon Skipper can be found patrolling grassy forest edges, particularly near streams, ponds, and wetlands.

Among the showiest of our butterflies, the Red-spotted Purple (Limenitis arthemis astyanax) is seen here on the leaves of a Black Cherry, its favored host plant.

Butterfly observers will do well to pay a visit to the new Susquehanna Riverlands State Park on Furnace Road north of Hellam in York County, Pennsylvania.

Trail to Schull's Rock Overlook — Upon arrival at Susquehanna Riverlands, drive back the gravel road for about a mile to the parking area at the edge of the agricultural field. Then, hike the trail through the woods and farm hedgerow to the Schull’s Rock overlook on the river. In the forests along this route, the understory is dominated by colonial stands of Common Pawpaw trees.

Along the lookout trail to Schull’s Rock, the Common Pawpaws’ large leaves help them to shade out potentially fast-growing competition. In proper growing situations, pawpaws develop clonal suckers that mature over time to create colonial stands of a single genetic plant.

Common Pawpaw understory. — A Common Pawpaw understory along the approach to Schull’s Rock.

During our recent visit to Schull’s Rock, dozens of Zebra Swallowtails were seen along the trail, many in the vicinity of their sole host plant, the Common Pawpaw. But even more were observed along the edges of the fields and woods where nectar sources like this Multiflora Rose were being visited by numbers of butterflies we normally see only among abundant species like Cabbage Whites. Absolutely amazing!

Scull's Rock Overlook — And the view of the Susquehanna and the Shock’s Mills railroad bridge at the mouth of Codorus Creek is pretty good too!

Common Pawpaw and Hooded Warbler — You can look for colonial stands of Common Pawpaw at other parks and preserves along the lower Susquehanna as well. Birds like this Hooded Warbler can sometimes be found among them in mature riparian forests along the steep slopes of the river gorge.

Common Pawpaw and Baltimore Oriole — A Baltimore Oriole in a Common Pawpaw along a forest edge.

Meanwhile in the treetops, the spring thrust of Neotropical migrants is drawing to a close. The Blackpoll Warbler is typically one of the last to transit the lower Susquehanna valley on its way to northern coniferous forests for summer. They’ve had an unusually protracted movement through the region this spring, the earliest individuals reported during late April. Though very difficult to see in the canopy of the mature trees where it feeds and sings, hearing one is often a benchmark for senior birders each spring. Older observers have often said of the Blackpoll Warbler’s high-pitched song, a rapid series of insect-like staccato “tseet” notes, that it was the first they could no longer detect as their ears started losing sensitivity.

In many tracts along the lower Susquehanna this spring, the American Redstart is turning out to be the most common nesting warbler. Conditions favoring their reproductive success in recent cycles, as well as good survival rates during their migrations and stays on wintering grounds, have filled many lowland forests with redstart songs in 2025. Is this the start of a trend or just an exceptionally good year? Time will tell.

Yet one more reason for a stroll in local forests this week is the chance to see and hear the Rose-breasted Grosbeak. Look for these Neotropical relatives of the cardinal nesting on territories in mature stands of deciduous trees like this Yellow Poplar, a species also known as the Tuliptree.

They spend nearly all their time among the canopy foliage of the largest timber…

May 19, 2025May 26, 2025

Back in the Day: Down on the Farm

Let us travel through time for just a little while to recall those sunny, late-spring days down on the farm—back when the rural landscape was a quiet, semi-secluded realm with little in the way of traffic, housing projects, or industrialized agriculture. Those among us who grew up on one of these family homesteads, or had friends who did, remember the joy of exploring the meadows, thickets, soggy springs, and woodlots they protected.

Low-intensity Farming — During much of the twentieth century, low-intensity agriculture provided a haven for wildlife. Periodic disturbances helped maintain cool-season grassland and early successional habitat for a number of species we currently find in decline.

For many of us, farmland was the first place we encountered and began to understand wildlife. Vast acreage provided an abundance of space to explore. And the discovery of each new creature provided an exciting experience.

Ned Smith's Birds of Field and Garden — Distributed by the Pennsylvania Game Commission, artist Ned Smith’s wildlife posters introduced many residents of the lower Susquehanna region to its birds and mammals. This poster of “Birds of Field and Garden” helped us learn what to expect and search for during our forays to the farm.

Today, high-intensity agriculture, relentless mowing, urban sprawl, and the increasing costs and demand for land have all conspired to seriously deplete habitat quality and quantity for many of the species we used to see on the local farm. Unfortunately for them, farm wildlife has largely been the victim of modern economics.

For old time’s sake, we recently passed a nostalgic afternoon at Middle Creek Wildlife Management Area examining what maintenance of traditional farm habitat has done and can do for breeding birds. Join us for a quick tour to remember how it used to be at the farm next door…

Always found nesting under the forebay of the barn, the Barn Swallow relentlessly pursued flying insects over the pond and meadow.

Eastern Meadowlarks arrived during March and April to begin nesting in their namesake. Their song, “spring-of-the-year”, heralded the new season.

Arriving in meadows and pastures during early May, the Eastern Kingbird provided for its nestlings by ambushing a variety of flying insects. By August, congregations of these birds could be found gathering along ponds and streams ahead of their fall migration.

In the cherry grove down by the creek, the Orchard Oriole would be singing incessantly to defend its territory.

Normally seed eaters through the colder months, American Goldfinches would regularly find a source of protein in the occupants of Eastern Tent Caterpillar nests.

Along the wet margins of the creek, Yellow Warblers would nest in the shrubs and small trees.

The “Traill’s Flycatcher” was a familiar find in low-lying areas of successional shrubs and small trees. Today, “Traill’s Flycatcher” is recognized as two distinct species, the Alder Flycatcher (Empidonax alnorum) and the Willow Flycatcher. In the lower Susquehanna valley, the latter (seen here) is by far the most common of the two.

During the nineteenth century, Eastern Bluebirds became a rarity on lower Susquehanna farms due to a combination of factors: pesticide (DDT) use, habitat loss, and competition with other birds for nest sites. The species saw a resurgence beginning in the 1970s with discontinuation of DDT applications and widespread provision of nesting boxes. Around human habitations, competition with invasive House Sparrows continues to be detrimental to their success.

Purple Martins and Tree Swallows — Purple Martins suffered a similar fate to the bluebirds. The potential for their recovery remains dubious and they continue to be very local breeders, fussy about selection of suitable man-made provisions for nesting. After considerable effort, Purple Martins have at last been attracted to nest in the condos placed for their use at Middle Creek Wildlife Management Area. In the artificial gourds, there are nesting Tree Swallows, a species which also benefits from the placement of boxes intended for bluebirds.

Abandoned fields and other successional habitats were and continue to be favored homes for Field Sparrows.

At almost any time of year, roving bands of Cedar Waxwings would suddenly visit old field habitat looking for berries among the shrubs and other pioneering woody growth. In early summer, after most species have already hatched their young, nesting would commence and these fruit eaters would transform into accomplished fly catchers.

During the twentieth century prior to the 1980s, Ring-necked Pheasant populations in the Lower Susquehanna River Watershed were comprised of breeding descendants of introduced birds supplemented by additional releases to maintain numbers sufficient for hunting. Year-round populations did and can reside in mosaic landscapes of early successional and grassland habitats, the latter including hay fields left unmowed through the nesting season.

Red-winged Blackbirds have always been a fixture of hay fields and meadows on farms. While the increase in mowing frequency has reduced their nesting success, they have persevered as a species by nesting earlier than other birds and by utilizing other landscape features such as densely vegetated stormwater basins for breeding sites.

Do you recall the last time you saw a Bobolink nesting in a hay field near you? Arriving in early May as a Neotropical migrant, the Bobolink requires a cool-season grassland such as hay field through at least July to complete its nesting cycle. Even earlier this century, we remember nesting Bobolinks being more widespread on farms throughout the region. Now, you almost have to go to Middle Creek if you want to see them.

Formerly more widespread in hay fields throughout the lower Susquehanna valley, the native Grasshopper Sparrow is yet another species falling victim to early mowing and intensive farming.

Cool-season Grasses — **Beautiful cool-season grasses waving in the spring breeze.** Meadows and hay fields can be managed to function as cool-season grasslands to provide nesting opportunities for many of the species we used to find down on the farm.

May 4, 2025May 5, 2025

Six Flowering Woody Plants

Here’s a look at six native shrubs and trees you can find blooming along forest edges in the lower Susquehanna valley right now.

The Black Locust (Robinia pseudoacacia), a member of the pea or legume family (Fabaceae), can be a dominant pioneer plant of sunny successional habitats, particularly on poor soils. Nodules along its roots fix nitrogen to help facilitate the growth of the intermediate and climax species of trees and shrubs that replace the pioneers. Initially armed with protective spines to reduce browsing, the Black Locust’s branches become mostly thornless as the tree matures.

The Pinxter Flower, also known as the Pink Azalea, is certainly a contender for our most spectacular native blossoming shrub;…

Spicebush Swallowtail on Pinxter Flower — …this Spicebush Swallowtail seems to like it too.

When in bloom, the Black Cherry is a common sight in regional woodlands. Often seen already covered with blossoms when young and shrub-like, many of these trees will continue flowering and producing fruit throughout the decades required to reach a mature height of 60 feet or more.

The Blackhaw is an understory shrub preferential to sun-dappled areas beneath a break in the forest canopy. Pollinated flowers later produce clusters of blue-black berries for birds and other wildlife.

Local old timers might remember hearing folklore that equates the northward advance of the blooming of the Flowering Dogwoods with the progress of the American Shad’s spring spawning run up the river. While this is hardly a scientific proclamation, it is likely predicated on what had been some rather consistent observation prior to the construction of the lower Susquehanna’s hydroelectric dams. In fact, we’ve found it to be a useful way to remind us that it’s time for a trip to the river shoreline below Conowingo Dam to witness signs of the spring fish migration each year. We’re headed that way now and will summarize our sightings for you in days to come.

October 12, 2024

Things to See While You’re Leaf Peeping

During your foray to view the colorful foliage of the autumn landscape, a little effort will reveal much more than meets the eye of the casual observer.

Fallen Foliage in the Forest — Don’t just stand there like a bump on a log, go for a stroll, watch your step, and have a look around. There’s a lot to see out there!

The dense understory of this forest on Blue Mountain consists almost exclusively of Witch-hazel (Hamamelis virginiana).

Witch-hazel in Flower — Witch-hazel is unique among our native flowering shrubs; it blooms in autumn.

Until we experience a heavy frost, some of our most beautiful butterflies, including this Common Buckeye, remain active along forest edges.

The arrival of large numbers of Yellow-rumped Warblers heralds the transition to movements of migrants that will spend the colder months in temperate climates like ours instead of continuing on to the tropics. In winter, small numbers of “yellow-rumps” sometimes linger in the Lower Susquehanna River Watershed, as long as a supply of wild berries is readily available.

The Palm Warbler, a persistent “tail wagger”, is another late-season migrant that occasionally spends the winter. The migration of these drab “Western Palm Warblers” will be followed in coming weeks by the more yellowish “Eastern Palm Warblers” of the eastern third of the species’ breeding range in Canada.

White-throated Sparrows are southbound and easily observed right now. Many will remain along our brushy forest edges for winter.

Another native sparrow, the familiar Dark-eyed Junco, is now arriving.

Yellow-bellied Sapsuckers — The Yellow-bellied Sapsucker is a secretive migratory woodpecker that is currently moving through the region on its way to southern pine forests for the winter. Juveniles like this one in the lower right remain close to their parents during migration and continue to beg for food.

The Pileated Woodpecker is a resident species in our mature forests and woodlands. We were showered by “sawdust” as we watched this one dismantling a rotted dead tree while searching for beetle grubs and other invertebrates.

You may see Eastern Bluebirds year-round in the lower Susquehanna valley, but many are migratory. A southbound push is currently transiting our area.

Hawk Watching on Blue Mountain at Boyd Big Tree Preserve. — Mix your leaf watching with hawk watching by visiting a ridgetop vista like this one at Boyd Big Tree Preserve Conservation Area on Blue Mountain north of Harrisburg and you can double your pleasure.

In addition to spectacular foliage, you stand a good chance of seeing an inquisitive Common Raven…

Screaming Red-tailed Hawk — …or a migrating Red-tailed Hawk that gives you a good scream as it passes by…

You may even double your fun by seeing two Common Ravens…

…or a couple of migrating Red-tailed Hawks…

You too can experience the joys of walking and chewing gum at the same time, so grab your field glasses, your camera, and your jacket, then spend lots of time outdoors this fall. You can see all of this and much more.

Don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to help you find a place to see both fall foliage and migrating birds of prey in coming weeks. And click the “Trees, Shrubs, and Woody Vines” tab to find a photo guide that can help you identify the autumn leaves you encounter during your outings.

August 31, 2024August 31, 2024

A Prescribed Fire Site After the Burn

Back on March 24th, we took a detailed look at the process involved in administering prescribed fire as a tool for managing grassland and early successional habitat. Today we’re going turn back the hands of time to give you a glimpse of how the treated site fared during the five months since the controlled burn. Let’s go back to Middle Creek Wildlife Management Area for a photo tour to see how things have come along…

Prescribed Fire application in March — Pennsylvania Game Commission crews administering prescribed fire on a grassland demonstration site back on March 16.

Prescribed Fire Site in May — By late May, native herbaceous perennial wildflowers including Joe-pye Weed had re-greened the site. One of the goals of the burn was to kill fire-sensitive woody plants, thus preventing the process of succession from reforesting the site.

Yellow-breasted Chat in May — Because prescribed fire is administered in a mosaic pattern that permits some early successional growth to remain until the next burn, birds including this thicket-nesting Yellow-breasted Chat are able to take advantage of the mixed habitat during their breeding season in May and June.

Prescribed Fire Site in August — By August, the site is a haven for native plants and animals.

Native Warm-season Grasses and Wildlflowers in August — The burn has promoted the growth and late-summer bloom of fire-tolerant native wildflowers and warm-season grasses…

Indiangrass in Flower — …including Indiangrass,…

Thin-leaved Coneflower, a plant also known as Brown-eyed Susan. — …Thin-leaved Coneflower (Rudbeckia triloba), a plant also known as Brown-eyed Susan,…

…and Joe-pye Weed, a plant butterflies find irresistible.

Eastern Tiger Swallowtail collecting nectar from Joe-pye Weed.

Black-morph Eastern Tiger Swallowtail — A black-morph Eastern Tiger Swallowtail collecting nectar from Spotted Knapweed (Centaurea steobe micranthos), a non-native invasive plant found growing in an area of the burn site missed by this year’s fire. While many non-native plants are unable to survive the flames and heat produced by prescribed fire, it isn’t an absolute cure-all. It doesn’t eliminate all invasive plants, it just keeps them from dominating a landscape by out-competing native species. Left unmanaged, Spotted Knapweed is a tough perennial invasive that can easily become one the species able to overtake a vulnerable grassland. It can be a stubborn survivor of some prescribed burns. On the plus side, butterflies really like it.

By August, native grassland plants in the prescribed fire area were already providing an abundance of seeds for birds including this American Goldfinch.

For larger birds like turkeys and pheasants, an abundance of Carolina Grasshoppers are providing a protein-dense food source in managed grasslands.

Elsewhere around the refuge at Middle Creek, prescribed fire and other management techniques are providing high-quality grassland habitat for numerous species of nesting birds…

Bobolink in Hay Field — …and in hay fields where mowing was delayed until the nesting season, including the fledging process, was completed earlier this month.

We hope you enjoyed this short photo tour of grassland management practices. Now, we’d like to leave you with one last set of pictures—a set you may find as interesting as we found them. Each is of a different Eastern Cottontail, a species we found to be particularly common on prescribed fire sites when we took these images in late May. The first two are of the individuals we happened to be able to photograph in areas subjected to fire two months earlier in March. The latter two are of cottontails we happened to photograph elsewhere on the refuge in areas not in proximity to ground treated with a prescribed burn or exposed to accidental fire in recent years.

Eastern Cottontail at a site subjected to prescribed fire earlier in the spring.

These first two rabbits are living the good life in a warm-season grass wonderland.

Eastern Cottontail with ticks. — Eastern Cottontail at a site not subjected to any recent fire activity.

Oh Deer! Oh Deer! These last two rabbits have no clock to track the time; they have only ticks. Better not go for a stroll with them Alice—that’s no wonderland! I know, I know, it’s time to go. See ya later.

August 30, 2024August 31, 2024

Aphrodite Fritillary

The Aphrodite Fritillary (Speyeria aphrodite), also known simply as the Aphrodite, is a brush-footed butterfly of deciduous, coniferous, and mixed forests. We found this female in a grassland margin between woodlots where prescribed fire was administered during the autumn of 2022 to reduce accumulations of natural fuels and an overabundance of invasive vegetation. A goal of the burn was to promote the growth of native species including the violets (Viola species) favored as larval host plants by this and other fritillaries.

By the time these adult butterflies make their reproductive flights in late summer, the violets that serve as larval host plants have gone dormant. To find patches of ground where the violets will come to life in spring, the female Aphrodite Fritillary has an ability to sense the presence of dormant roots, probably by smell. Upon finding an area where suitable violets will begin greening up next year, she’ll deposit her eggs. The eggs overwinter, then hatch to feed on the tender new violet leaves of spring.

July 27, 2024July 27, 2024

Wildflower Meadow Update

Do you recall our “Photo of the Day” from seven months ago…

Riverfront Park Wildflower Meadow — Here’s something to look forward to in the new year. The good citizens of East Donegal Township in Lancaster County have partnered with Alliance for the Chesapeake Bay to establish an extensive wildflower meadow on what had been a mowed field of turf grass at Riverside Park in the Susquehanna floodplain near Marietta. As the photo shows, the lawn plants have been eliminated in preparation for seeding with a diverse assortment of native grasses and wildflowers to provide habitat for birds and pollinators including butterflies, bees, and other insects. Once established, the meadow’s extensive vegetative growth will help reduce stormwater runoff by better infiltrating rainfall to recharge the aquifer. During flood events, the plantings will provide soil stabilization and increase the ability of the acreage to uptake nutrients, thus reducing the negative impact of major storms on the quality of water in the river and in Chesapeake Bay. Check the project’s progress by stopping by from time to time in 2024!

Well, here’s what that site looks like today…

And there are pollinating insects galore, most notably butterflies…

A Cabbage White collecting nectar on Blue Vervain.

A Sulphur — A Clouded or Orange Sulphur among the grasses in the meadow.

The Least Skipper is our tiniest butterfly.

The Little Glassywing (Vernia verna), this one feeding on vervain nectar, deposits its eggs on Purpletop grass, which then functions as the host plant for this butterfly’s larvae.

A Summer Azure (Celastrina neglecta) feeding on the nectar of a Black-eyed Susan.

An Eastern Tiger Swallowtail on Blue Vervain. Nearby Yellow (Tulip) Poplars and other trees serve as host plants for this butterfly’s larvae.

The Sachem, this one visiting a Black-eyed Susan, is a variable species with a range that normally lies south of the 40th parallel, the line of latitude that intersects the Susquehanna in the area of the Conejohela Flats at Washington Boro.

A Sachem visiting the blooms of Oxeye sunflower. During recent weeks, scorching winds from the south and southwest have transported an abundance of these vagrant skippers into the lower Susquehanna valley and beyond.

Here and there among the meadow’s plantings we noticed one of our favorites starting to flower, the Partridge Pea.

Partridge Pea happens to be a host plant for another vagrant from the south, the big, lime-yellow Cloudless Sulphur. We saw at least half a dozen patrolling the meadow.

Why on earth would anyone waste their time, energy, and money mowing grass when they could have this? Won’t you please consider committing graminicide this fall? That’s right, kill that lawn—at least the majority of it. Then visit the Ernst Seed website, buy some “Native Northeast Wildlflower Mix” and/or other blends, and get your meadow planted in time for the 2025 growing season. Just think of all the new kinds of native plants and animals you’ll be seeing. It could change your life as well as theirs.

A Snowberry Clearwing (Hemaris diffinis), more commonly known as a hummingbird moth, visits the flowers of Blue Vervain in the Riverfront Park wildflower meadow.

May 24, 2024May 25, 2024

Arboreal Birds and Tent Caterpillars

During the past week, we’ve been exploring wooded slopes around the lower Susquehanna region in search of recently arrived Neotropical birds—particularly those migrants that are singing on breeding territories and will stay to nest. Coincidentally, we noticed a good diversity of species in areas where tent caterpillar nests were apparent.

Eastern Tent Caterpillar Nest — The conspicuous nest of the Eastern Tent Caterpillar (Malacosoma americanum), a native species of moth. The first instar of the larval caterpillars hatch in early spring from egg masses laid on the limbs of the host tree by an adult female moth during the previous spring. Soon after they begin feeding on the host tree’s first tender shoots, these tiny, seldom-noticed larvae start communal construction of a silk tent to act as a shelter and greenhouse-like solar collector that will both provide protection from the elements and expedite their growth.

Here’s a sample of the variety of Neotropical migrants we found in areas impacted by Eastern Tent Caterpillars. All are arboreal insectivores, birds that feed among the foliage of trees and shrubs searching mostly for insects, their larvae, and their eggs.

The Yellow-throated Vireo nests, feeds, and spends the majority of its time feeding among canopy foliage.

The Eastern Wood-Pewee is a flycatcher found in mature woodlands. It feeds not only among the limbs and leaves, but is an aerial predator as well.

The Northern Parula nests in mature forests along rivers and on mountainsides, particularly where mature trees are draped with thick vines.

The Hooded Warbler (Setophaga citrina) is found among thick understory growth on forested slopes.

The Ovenbird builds a domed, oven-like nest on the ground and forages in the canopy.

The Kentucky Warbler (Geothlypis formosa) nests in woodland undergrowth, often near steep, forested slopes.

The Worm-eating Warbler (Helmitheros vermivorum) nests among woody understory growth on forested hillsides.

The Scarlet Tanager is often difficult to observe because of its affinity for the canopy of mature forest trees.

In the locations where these photographs were taken, ground-feeding birds, including those species that would normally be common in these habitats, were absent. There were no Gray Catbirds, Carolina Wrens, American Robins or other thrushes seen or heard. One might infer that the arboreal insectivorous birds chose to establish nesting territories where they did largely due to the presence of an abundance of tent caterpillars as a potential food source for their young. That could very well be true—but consider timing.

**Already Gone-** By the time Neotropical migrants arrive in our area, the larval stages of the Eastern Tent Caterpillar’s life cycle are already coming to an end. The nests that these native insects constructed to capture the energy of the springtime sun have allowed the larvae to exit and browse foliage when conditions were suitable, then return for shelter when they were not. While inside, the larvae could move among the chambers of their structure to find locations with a temperature that best suited their needs. Therein the solar heating and communal warmth sped up digestion and growth.

Having left arboreal environs, Eastern Tent Caterpillar larvae are now food for ground-feeding birds like our resident Wild Turkeys. They need only get past the bristly hairs on the caterpillar’s back and the foul taste that may result from its limited diet of cyanogenic Black Cherry leaves.

The arboreal Yellow-billed Cuckoo (seen here) and its close relative the Black-billed Cuckoo (Coccyzus erythropthalmus) are the two species of birds in our area known to regularly feed on bristly tent caterpillars. But having just arrived from the tropics to nest, they’ll need to rely on other insects and their larvae as sources of food for their young.

Black Cherry defoliated by Eastern Tent Caterpillars. — Final-instar Eastern Tent Caterpillars often defoliate Black Cherry trees before moving to the ground to pupate. Their timing allows them to feed on the fresh foliage while it is still young and tender, and to largely avoid becoming food for the waves of Neotropical birds that arrive in the lower Susquehanna basin in May.

So why do we find this admirable variety of Neotropical bird species nesting in locations with tent caterpillars? Perhaps it’s a matter of suitable topography, an appropriate variety of native trees and shrubs, and an attractive opening in the forest.

Black Cherry in Flower — The end of the Eastern Tent Caterpillar’s larval surge may spell the end of their nests for the year, but it’s not the end for the Black Cherry and other host trees in the Prunus (cherry) and Malus (apple) genera. Because it’s still early in the season, they have plenty of time to re-leaf and many will still flower and produce fruit. Those flowers and foliage will attract numerous other insects (including pollinators) that benefit breeding birds.

The Blue-winged Warbler inhabits shrubby breaks in the forest such as this utility right-of-way where Black Cherry trees have sprouted after their seeds arrived in waste deposited by fruit-eating (frugivorous) birds. Already attractive to a variety of insectivores, these openings soon lure egg-laying Eastern Tent Caterpillar moths to the cherry trees growing therein. Even in dense forest, a small clearing created by a cluster of dead trees makes good bird habitat and will sooner or later be visited by fruit-eating species that will inadvertently sow seeds of Black Cherry, starting yet another stand of host trees for Eastern Tent Caterpillars. It’s the gap in the forest that often attracts the birds, some of which plant the host trees, which sometimes entice Eastern Tent Caterpillar moths to lay their eggs.

Red-Eyed Vireo — **Adapt and Reuse-** A Red-eyed Vireo visits an Eastern Tent Caterpillar nest…

Here in the Lower Susquehanna River Watershed, the presence of Eastern Tent Caterpillar nests can often be an indicator of a woodland opening, natural or man-made, that is being reforested by Black Cherry and other plants which improve the botanical richness of the site. For numerous migratory Neotropical species seeking favorable places to nest and raise young, these regenerative areas and the forests surrounding them can be ideal habitat. For us, they can be great places to see and hear colorful birds.

March 24, 2024August 30, 2024

Prescribed Fire: Controlled Burns for Forest and Non-forest Habitats

Homo sapiens owes much of its success as a species to an acquired knowledge of how to make, control, and utilize fire. Using fire to convert the energy stored in combustible materials into light and heat has enabled humankind to expand its range throughout the globe. Indeed, humans in their furless incomplete mammalian state may have never been able to expand their populations outside of tropical latitudes without mastery of fire. It is fire that has enabled man to exploit more of the earth’s resources than any other species. From cooking otherwise unpalatable foods to powering the modern industrial society, fire has set man apart from the rest of the natural world.

In our modern civilizations, we generally look at the unplanned outbreak of fire as a catastrophe requiring our immediate intercession. A building fire, for example, is extinguished as quickly as possible to save lives and property. And fires detected in fields, brush, and woodlands are promptly controlled to prevent their exponential growth. But has fire gone to our heads? Do we have an anthropocentric view of fire? Aren’t there naturally occurring fires that are essential to the health of some of the world’s ecosystems? And to our own safety? Indeed there are. And many species and the ecosystems they inhabit rely on the periodic occurrence of fire to maintain their health and vigor.

**For the war effort-** The campaign to reduce the frequency of forest fires got its start during World War II with distribution of this poster in 1942. The goal was to protect the nation’s timber resources from accidental or malicious loss due to fire caused by man-made ignition sources. The release of the Walt Disney film “Bambi” during the same year and the adoption of the Smokey the Bear mascot in 1944 softened the message’s delivery, but the public relations outreach continued to be a key element of a no-fire policy to save trees for lumber. Protection and management of healthy forest ecosystems in their entirety has only recently become a priority. (National Archives image)

Man has been availed of the direct benefits of fire for possibly 40,000 years or more. Here in the Lower Susquehanna River Watershed, the earliest humans arrived as early as 12,000 years ago—already possessing skills for using fire. Native plants and animals on the other hand, have been part of the ever-changing mix of ecosystems found here for a much longer period of time—millions to tens of millions of years. Many terrestrial native species are adapted to the periodic occurrence of fire. Some, in fact, require it. Most upland ecosystems need an occasional dose of fire, usually ignited by lightning (though volcanism and incoming cosmic projectiles are rare possibilities), to regenerate vegetation, release nutrients, and maintain certain non-climax habitat types.

But much of our region has been deprived of natural-type fires since the time of the clearcutting of the virgin forests during the eighteenth and nineteenth centuries. This absence of a natural fire cycle has contributed to degradation and/or elimination of many forest and non-forest habitats. Without fire, a dangerous stockpile of combustible debris has been collecting, season after season, in some areas for a hundred years or more. Lacking periodic fires or sufficient moisture to sustain prompt decomposition of dead material, wildlands can accumulate enough leaf litter, thatch, dry brush, tinder, and fallen wood to fuel monumentally large forest fires—fires similar to those recently engulfing some areas of the American west. So elimination of natural fire isn’t just a problem for native plants and animals, its a potential problem for humans as well.

Indiangrass on Fire — Indiangrass (seen here), Switchgrass, Big Bluestem, and Little Bluestem are native species requiring periodic forms of disturbance to eliminate competition by woody plants. These warm-season grasses develop roots that penetrate deep into the soil, sometimes to depths of six feet or more, allowing them to survive severe drought and flash fire events. In the tall grass prairies, these extensive root systems allow these grasses to return following heavy grazing by roaming herds of American Bison (Bison bison). Without these habitat disturbances, warm season grasslands succumb to succession in about seven years. With their periodic occurrence, the plants thrive and provide excellent wildlife habitat, erosion control, and grazing forage.

To address the habitat ailments caused by a lack of natural fires, federal, state, and local conservation agencies are adopting the practice of “prescribed fire” as a treatment to restore ecosystem health. A prescribed fire is a controlled burn specifically planned to correct one or more vegetative management problems on a given parcel of land. In the Lower Susquehanna River Watershed, prescribed fire is used to…

- - Eliminate dangerous accumulations of combustible fuels in woodlands.
  - Reduce accumulations of dead plant material that may harbor disease.
  - Provide top kill to promote oak regeneration.
  - Regenerate other targeted species of trees, wildflowers, grasses, and vegetation.
  - Kill non-native plants and promote growth of native plants.
  - Prevent succession.
  - Remove woody growth and thatch from grasslands.
  - Promote fire tolerant species of plants and animals.
  - Create, enhance, and/or manage specialized habitats.
  - Improve habitat for rare species (Regal Fritillary, etc.)
  - Recycle nutrients and minerals contained in dead plant material.

Let’s look at some examples of prescribed fire being implemented right here in our own neighborhood…

Prescribed Fire at Fort Indiantown Gap — Prescribed fire is used regularly at Fort Indiantown Gap Military Reservation in Lebanon County, Pennsylvania, to keep accumulations of woody and herbaceous fuels from accumulating on and around the training range areas where live ordinance and other sources of ignition could otherwise spark large, hard-to-control wildfires.

Prescribed fire in grassland. — A prescribed fire in late winter prevents this grassland consisting of Big Bluestem and native wildflowers from being overtaken by woody growth and invasive species. Fires such as this that are intended to interrupt the process of succession are repeated at least every three to five years.

Prescribed Fire to Control Invasive Species — In its wildlife food plots, prescribed fire is used by the Pennsylvania Game Commission to prevent succession and control invasive species such as Multiflora Rose, instead promoting the growth of native plants.

A woodlot understory choked with combustible fuels and tangles of invasive Multiflora Rose. — An example of a woodlot understory choked with combustible fuels and dense tangles of invasive Multiflora Rose. A forester has the option of prescribing a dose of dormant-season fire for a site like this to reduce the fuel load, top kill non-native vegetation, and regenerate native plants.

Precribed Fire to Eliminate Woody Growth — A dose of prescribed fire was administered on this grassland to kill the woody growth of small trees beginning to overtake the habitat by succession.

Precribed Fire Education Sign at middle creek Wildlife Management Area — The Pennsylvania Game Commission employs prescribed fire at Middle Creek Wildlife Management Area and on many of their other holdings to maintain grasslands.

Prescribed fire is used to eliminate invasive species including Multiflora Rose from grasslands at Middle Creek W.M.A. Annual burns on the property are conducted in a mosaic pattern so that each individual area of the grassland is exposed to the effects of fire only once every two to five years. Without fire or some type of mechanical or chemical intervention, succession by woody trees and shrubs would take hold after about seven years.

Prescribed fire is planned for a fraction of total grassland acreage at Middle Creek W.M.A. each year. Another section of the mosaic is targeted in the following year and yet another in the year that follows that. Because burns are conducted in the spring, grassland cover is available for wildlife throughout the winter. And because each year’s fire burns only a portion of the total grassland acreage, wildlife still has plenty of standing grass in which to take shelter during and after the prescribed fire.

Prescribed Burn Maintains Savanna-like Habitat — On a few sites in the Lower Susquehanna River Watershed , prescribed fire is being used to establish and maintain savanna-like grasslands. This one, located on a dry, south-facing slope near numerous man-made sources of ignition, can easily be dosed with periodic prescribed burns to both prevent succession and reduce fuel accumulations that may lead to a devastating extreme fire.

Pitch Pines in Savanna-like Habitat — One year following a prescribed burn, this is the autumn appearance of a savanna-like habitat with fire-tolerant Pitch Pine (Pinus rigida), Bear Oak, warm-season grasses, and a variety of nectar-producing wildflowers for pollinators. These ecosystems are magnets for wildlife and may prove to be a manageable fit on sun-drenched sites adjacent to man-made land disturbances and their sources of ignition.

Red-headed Woodpecker Adult and Juvenile — Savanna-like grasslands with oaks and other scattered large trees, some of them dead, make attractive nesting habitat for the uncommon Red-headed Woodpecker.

Wild Turkey in Savanna-like Habitat — Prescribed fire can benefit hungry Wild Turkeys by maintaining savanna-like grasslands for an abundance of grasshoppers and other insects in summer and improving the success of mast-producing oaks for winter.

In the Lower Susquehanna River Watershed, the caterpillar of the rare Eastern Buck Moth feeds on the foliage of the Bear Oak, also known as the Scrub Oak, a shrubby species that relies upon periodic fire to eliminate competition from larger trees in its early successional habitat.

Leaves of the Bear Oak in fall. The Bear Oak regenerates readily from top kill caused by fire.

Reed Canary Grass (Phalaris arundinacea) is a native cool-season grass with a colorful inflorescence in spring. But given the right situation, it can aggressively overtake other species to create a pure stand lacking biodiversity. It is one of the few native species which is sometimes labelled “invasive”.

Prescribed Burn to Reduce Prevalence of Reed Canary Grass — Prescribed fire can be used to reduce an overabundance of Reed Canary Grass and its thatch in wetlands. Periodic burning can help restore species diversity in these habitats for plants and animals including rare species such as the endangered Bog Turtle (Glyptemys muhlenbergii).

On the range areas at Fort Indiantown Gap in Lebanon County, Pennsylvania, disturbances by armored vehicles mimic the effects of large mammals such as the American Bison which periodically trampled grasses to prevent succession and the establishment of woody plants on its prairie habitat. To supplement the activity of the heavy vehicles and to provide suitable habitat for the very rare Regal Fritillary (Speyeria idalia) butterflies found there, prescribed fire is periodically employed to maintain the grasslands on the range. These burns are planned to encourage the growth of “Fort Indiantown Gap Little Bluestem” grass as well as the violets used as host plants by the Regal Fritillary caterpillars. These fires also promote growth of a variety of native summer-blooming wildflowers to provide nectar for the adults butterflies.

Depiction of Pennsylvania's Last American Bison, Killed in Union County in 1801. (Exhibit: State Museum of Pennsylvania, Harrisburg) — A last record of a wild American Bison killed in Pennsylvania was an animal taken in the Susquehanna watershed in Union County in 1801. The species is thereafter considered extirpated from the state. Since that time, natural disturbances needed to regenerate warm-season grasses have been limited primarily to fires and riverine ice scour. The waning occurrence of both has reduced the range of these grasses and their prairie-like ecosystems in the commonwealth. (Exhibit: State Museum of Pennsylvania, Harrisburg)

A male Regal Fritillary on the range at Fort Indiantown Gap, where armored vehicles and prescribed fire provide suitable prairie-like habitat for this vulnerable species.

Honey Bee Collecting Minerals After Prescribed Burn — Prescribed fires return the nutrients and minerals contained in dead plant material to the soil. Following these controlled burns, insects like this Honey Bee can often be seen collecting minerals from the ashes.

Fly Collecting Minerals from Burned Grasses — A Greenbottle Fly gathering minerals from the ash following a prescribed burn.

In Pennsylvania, state law provides landowners and crews conducting prescribed fire burns with reduced legal liability when the latter meet certain educational, planning, and operational requirements. This law may help encourage more widespread application of prescribed fire in the state’s forests and other ecosystems where essential periodic fire has been absent for so very long. Currently in the Lower Susquehanna River Watershed, prescribed fire is most frequently being employed by state agencies on state lands—in particular, the Department of Conservation and Natural Resources on State Forests and the Pennsylvania Game Commission on State Game Lands. Prescribed fire is also part of the vegetation management plan at Fort Indiantown Gap Military Reservation and on the land holdings of the Hershey Trust. Visitors to the nearby Gettysburg National Military Park will also notice prescribed fire being used to maintain the grassland restorations there.

For crews administering prescribed fire burns, late March and early April are a busy time. The relative humidity is often at its lowest level of the year, so the probability of ignition of previous years’ growth is generally at its best. We visited with a crew administering a prescribed fire at Middle Creek Wildlife Management Area last week. Have a look…

Members of a Pennsylvania Game Commission burn crew provide visitors to Middle Creek Wildlife Management Area with an overview of prescribed fire. — Members of a Pennsylvania Game Commission burn crew provide visitors to Middle Creek Wildlife Management Area with an overview of prescribed fire and the equipment and techniques they use to conduct a burn.

Burn Boss Checking Weather — Pennsylvania Game Commission Southeast Region Forester Andy Weaver will fulfill the role of Burn Boss for administering this day’s dose of fire. His responsibilities include assessing the weather before the burn and calculating a probability of ignition.

Burn Boss Briefing Crew — The Burn Boss briefs personnel with information on site layout, water supply location(s), places of refuge, emergency procedures, the event’s goals and plan of action, crew assignments, and the results of the weather check: wind from the northwest at 5 miles per hour, temperature 48 degrees, and the relative humidity 63%. Today’s patient is a parcel of warm-season grasses receiving a dose of fire to eliminate invasive non-native plants, woody growth, and thatch. The probability of ignition is 20%, but improving by the minute.

Prescribed Fire Test Burn — To begin the burn, a test fire is started in the downwind corner of the parcel, which also happens to be the bottom of the slope. Fuel ignition is good. The burn can proceed.

Igniting the Fire — Crews proceed uphill from the location of the test fire while igniting combustibles along both flanks of the area being treated.

Prescribed Fire Crew Member with Equipment — A drip torch is used to ignite the dried stems and leaves of warm-season grasses and wildflowers. Each member of the burn crew wears Nomex fire-resistant clothing and carries safety equipment including a two-way radio, a hydration pack, and a cocoon-like emergency fire shelter.

Wildfire ATV — An all-terrain vehicle equipped with various tools, a fire pump, hose, and a small water tank accompanies the crew on each flank of the fire.

Effective Fire Break — With green cool-season grasses already growing on the trails surrounding the burn zone, very little water was used to contain this prescribed fire. Where such convenient fire breaks don’t already exist, crews carry tools including chain saws, shovels, and leaf blowers to create their own. They also carry flame swatters, backpack water pumps, shovels, and other tools to extinguish fires if necessary. None of these items were needed to control this particular fire.

Halting the Process of Succession in a Grassland with Prescribed Fire — This fast-burning fire provides enough heat to damage the cambium layer of the woody tree and shrub saplings in this parcel being maintained as a grassland/wildflower plot, thus the process of succession is forestalled. Burns conducted during previous years on this and adjacent fields have also controlled aggressive growth of invasive Multiflora Rose and Olives (Elaeagnus species).

Containing the Fire on the Flanks — Crews proceed up the slope while maintaining the perimeter by igniting dry plant material along the flanks of the burn zone.

The Crew Monitors the Burn — Ignition complete, the crews monitor the fire.

Prescribed Fire: Natural Mosaic-style Burn Pattern — The Burn Boss surveys the final stages of a safe and successful prescribed fire. The fire has left behind a mosaic of burned and unburned areas, just as a naturally occurring event may have done. Wildlife dodging the flames may be taking refuge in the standing grasses, so there is no remedial attempt to go back and ignite these areas. They’ll be burned during prescribed fires in coming years.

By June, this grassland will again be lush and green with warm-season grasses and blooming wildflowers like this Common Milkweed being visited by a Great Spangled Fritillary.

And later in the summer, Eastern Tiger Swallowtails on Joe-pye Weed.

Bobolinks in Indiangrass — Bobolinks glow in the late August sun while taking flight from a stand of warm-season grasses maintained using springtime prescribed fire. The small dots on the dark background at the top of the image are multitudes of flying insects, many of them pollinators. The vegetation is predominately Indiangrass, excellent winter cover for birds, mammals, and other wildlife.

Prescribed burns aren’t a cure-all for what ails a troubled forest or other ecosystem, but they can be an effective remedy for deficiencies caused by a lack of periodic episodes of naturally occurring fire. They are an important option for modern foresters, wildlife managers, and other conservationists.

February 22, 2024February 24, 2024

Time to Order Trees and Shrubs for Spring

It’s that time of year. Your local county conservation district is taking orders for their annual tree sale and it’s a deal that can’t be beat. Order now for pickup in April.

The prices are a bargain and the selection includes the varieties you need to improve wildlife habitat and water quality on your property. For species descriptions and more details, visit each tree sale web page (click the sale name highlighted in blue). And don’t forget to order packs of evergreens for planting in mixed clumps and groves to provide winter shelter and summertime nesting sites for our local native birds. They’re only $12.00 for a bundle of 10.

Mature Trees in a Suburban Neighborhood — It’s the most desirable block in town, not because the houses are any different from others built during the post-war years of the mid-twentieth century, but because the first owners of these domiciles had the good taste and foresight to plant long-lived trees on their lots, the majority of them native species. Pin Oak, Northern Red Oak, Yellow Poplar, Flowering Dogwood (Cornus florida), Eastern Red Cedar, Eastern White Pine, Eastern Hemlock, Norway Spruce, and American Holly dominate the landscape and create excellent habitat for birds and other wildlife. These 75-year-old plantings provide an abundance of shade in summer and thermal stability in winter, making it a “cool” place to live or take a stroll at any time of the year.

Cumberland County Conservation District Annual Tree Seedling Sale—

Orders due by: Friday, March 22, 2024

Pickup on: Thursday, April 18, 2024 or Friday, April 19, 2024

Cumberland County Conservation District is taking orders for Common Winterberry, the ideal small shrub for wet soil anywhere on your property. To get berries, you’ll need both males and females, so buy a bunch and plant them in a clump or scattered group.

To live for a century or more like this towering giant, a Pin Oak needs to grow in well-drained soils with adequate moisture. These sturdy shade providers do well along streams and on low ground receiving clean runoff from hillsides, roofs, streets, and parking areas. As they age, Pin Oaks can fail to thrive and may become vulnerable to disease in locations where rainfall is not adequately infiltrated into the soil. Therefore, in drier areas such as raised ground or slopes, avoid the Pin Oak and select the more durable Northern Red Oak for planting. This year, Pin Oaks are available from the Cumberland and Lancaster County Conservation Districts, while Dauphin, Lancaster, Lebanon, and York Counties are taking orders for Northern Red Oaks.

The Cumberland County Conservation District is again offering a “Showy Northeast Native Wildflower and Grass Mix” for seeding your own pollinator meadow or garden. It consists of more than twenty species including this perennial favorite, Purple Coneflower.

Dauphin County Conservation District Seedling Sale—

Orders due by: Monday, March 18, 2024

Pickup on: Thursday, April 18, 2024 or Friday, April 19, 2024

The Eastern Redbud is small tree native to our forest edges, particularly in areas of the Piedmont Province with Triassic geology (Furnace Hills, Conewago Hills, Gettysburg/Hammer Creek Formations, etc.) Also known as the Judas Tree, the redbud’s brilliant flowers are followed by heart-shaped leaves. As seen here, it is suitable for planting near houses and other buildings. Eastern Redbud seedlings are being offered through tree sales in Dauphin, Cumberland, and Lancaster Counties.

Lancaster County Annual Tree Seedling Sale—

Orders due by: Friday, March 8, 2024

Pickup on: Friday, April 12, 2024

The Yellow Poplar, often called Tuliptree or Tulip Poplar for its showy flowers, is a sturdy, fast-growing deciduous tree native to forests throughout the Lower Susquehanna River Watershed. Its pole-straight growth habit in shady woodlands becomes more spreading and picturesque when the plant is grown as a specimen or shade tree in an urban or suburban setting. The Yellow Poplar can live for hundreds of years and is a host plant for the Eastern Tiger Swallowtail butterfly. It is available this year from the Lancaster County Conservation District.

The American Sweetgum, also known as Sweet Gum, is a large, long-lived tree adorned with a mix of vibrant colors in autumn.

American Goldfinches and Pine Siskin on Sweet Gum — Ever wonder where all the American Goldfinches and particularly the Pine Siskins go after passing through our region in fall? Well, many are headed to the lowland forests of the Atlantic Coastal Plain where they feed on an abundance of seeds contained in spiky American Sweetgum fruits. In the Piedmont and Ridge and Valley Provinces of the Lower Susquehanna River Watershed, American Sweetgum transplants can provide enough sustenance to sometimes lure our friendly finches into lingering through the winter.

Sweet Gum in a Beaver Pond — The American Sweetgum is a versatile tree. It can be planted on upland sites as well as in wet ground along streams, lakes, and rivers. In the beaver pond seen here it is the dominate tree species. This year, you can buy the American Sweetgum from the Lancaster County Conservation District.

"Red-twig Dogwood" — “Red-twig Dogwood” is a group of similar native shrubs that, in our region, includes Silky Dogwood and the more northerly Red-Osier Dogwood (Cornus sericea). Both have clusters of white flowers in spring and showy red twigs in winter. They are an excellent choice for wet soils. Landscapers often ruin these plants by shearing them off horizontally a foot or two from the ground each year. To produce flowers and fruit, and to preserve winter attractiveness, trim them during dormancy by removing three-year-old and older canes at ground level, letting younger growth untouched.

Silky Dogwood Stream Buffer — “Red-twig Dogwoods” make ideal mass plantings for streamside buffers and remain showy through winter, even on a gloomy day. They not only mitigate nutrient and sediment pollution, they provide excellent food and cover for birds and other wildlife. Both Silky and Red-osier Dogwoods are available for sale through the Lancaster County Conservation District as part of their special multi-species offers, the former is included in its “Beauty Pack” and the latter in its “Wildlife Pack”. The similar Gray Dogwood (Cornus racemosa) is being offered for sale by the York County Conservation District.

Lebanon County Conservation District Tree and Plant Sale—

Orders due by: Friday, March 8, 2024

Pickup on: Friday, April 19, 2024

Common Pawpaw flower — The unique maroon flowers of the Common Pawpaw produce banana-like fruits in summer. These small native trees grow best in damp, well-drained soils on slopes along waterways, where they often form clonal understory patches. To get fruit, plant a small grove to increase the probability of pollination. The Common Pawpaw is a host plant for the Zebra Swallowtail butterfly. It is available through both the Lebanon and Lancaster County sales.

The Eastern Red Cedar provides excellent food, cover, and nesting sites for numerous songbirds. Planted in clumps of dozens or groves of hundreds of trees, they can provide winter shelter for larger animals including deer and owls. The Eastern Red Cedar is being offered for purchase through both the Lebanon and Lancaster County Conservation Districts.

Hybrid American Chestnut — Care to try your hand at raising some chestnuts? Lebanon County Conservation District has hybrid American Chestnut seedlings for sale.

Perry County Conservation District Tree Sale—

Orders due by: Sunday, March 24, 2024

Pickup on: Thursday, April 11, 2024

Pollinator Garden — In addition to a selection of trees and shrubs, the Perry County Conservation District is again selling wildflower seed mixes for starting your own pollinator meadow or garden. For 2024, they have both a “Northeast Perennials and Annuals Mix” and a “Butterfly and Hummingbird Seed Mix” available. Give them a try so you can give up the mower!

Again this year, Perry County is offering bluebird nest boxes for sale. The price?—just $12.00.

York County Conservation District Seedling Sale—

Orders due by: Friday, March 15, 2024

Pickup on: Thursday, April 11, 2024

Buttonbush flower — The Buttonbush, a shrub of wet soils, produces a cosmic-looking flower. It grows well in wetlands, along streams, and in rain gardens. Buttonbush seedlings are for sale from both the York and Lancaster County Conservation Districts.

To get your deciduous trees like gums, maples, oaks, birches, and poplars off to a safe start, conservation district tree sales in Cumberland, Dauphin, Lancaster, and Perry Counties are offering protective tree shelters. Consider purchasing these plastic tubes and supporting stakes for each of your hardwoods, especially if you have hungry deer in your neighborhood.

Deciduous Tree Planting Protected by Shelters — Tree shelters protect newly transplanted seedlings from browsing deer, klutzy hikers, visually impaired mower operators, and other hazards.

There you have it. Be sure to check out each tree sale’s web page to find the selections you like, then get your order placed. The deadlines will be here before you know it and you wouldn’t want to miss values like these!

October 11, 2023

Photo of the Day

A Monarch butterfly takes a break from its southbound migration to energize on nectar from a goldenrod flower.

September 15, 2023

The Gray Comma: Now You See Me, Now You Don’t

Check out this and other local species by clicking the “Butterflies” tab at the top of this page.

September 11, 2023September 12, 2023

A Visit to a Beaver Pond

To pass the afternoon, we sat quietly along the edge of a pond created recently by North American Beavers (Castor canadensis). They first constructed their dam on this small stream about five years ago. Since then, a flourishing wetland has become established. Have a look.

A beaver lodge. — The beaver lodge was built among shrubs growing in shallow water in the middle of the pond.

Woolgrass in a beaver pond. — Woolgrass (Scirpus cyperinus) is a bulrush that thrives as an emergent and as a terrestrial plant in moist soils bordering the pond.

A male Common Whitetail dragonfly keeping watch over his territory.

A Twelve-spotted Skimmer perched on Soft Rush.

A Blue Dasher dragonfly seizing a Fall Field Cricket (Gryllus pennsylvanicus).

A Spicebush Swallowtail visiting Cardinal Flower. — A Spicebush Swallowtail visiting a Cardinal Flower.

A Green Heron looking for small fish, crayfish, frogs, and tadpoles.

A Green Heron stalks potential prey. — The Green Heron stalking potential prey.

A Wood Duck feeding on Lesser Duckweed. — A Wood Duck feeding on the tiny floating plant known as Lesser Duckweed (Lemna minor).

A Least Sandpiper feeding along the muddy edge of a beaver pond. — A Least Sandpiper poking at small invertebrates along the muddy edge of the beaver pond.

A Solitary Sandpiper testing the waters for proper feeding depth.

A Pectoral Sandpiper searches for its next morsel of sustenance.

A Sora rail in a beaver pond. — The Sora (Porzana carolina) is a seldom seen rail of marshlands including those created by North American Beavers. Common Cattails, sedges, and rushes provide these chicken-shaped wetland birds with nesting and loafing cover.

Isn’t that amazing? North American Beavers build and maintain what human engineers struggle to master—dams and ponds that reduce pollution, allow fish passage, and support self-sustaining ecosystems. Want to clean up the streams and floodplains of your local watershed? Let the beavers do the job!

August 21, 2023August 22, 2023

Wild Senna, a Showy Background Plant for Your Wildflower Garden

Looking for a native wildflower that’s tall, showy, and a great choice for attracting wildlife, especially butterflies and bees? Then check out Wild Senna (Senna hebecarpa).

Wild Senna in a roadside wildflower garden on Pennsylvania State Gamelands. — Wild Senna currently blooming in a roadside wildflower garden on Pennsylvania State Game Lands.

Wild Senna, also known as American Senna, is a host plant for the larvae of Cloudless Sulphur and Sleepy Orange (Eurema nicippe) butterflies. It thrives in almost any moist, well-drained soil in habitats including open woodlands, forest edges, meadows, and gardens like yours. Its height at flowering ranges from three to six feet. If you prefer, this perennial wildflower can even be cultivated as a shrub-like form. It is easily grown from seed, which is available from Ernst Conservation Seeds of Meadville, Pennsylvania, as well as numerous other vendors. And don’t forget to give Wild Senna’s two close relatives, Partridge Pea and Maryland Senna, a try as well. They attract the same species of butterflies and are just as easy to grow. You’ll like ’em.

Close-up view of a Wild Senna flower cluster. Typical of members of the pea family, the seeds of all native Senna species develop within pods after blooming and are sought after by wildfowl (Galliformes), particularly Northern Bobwhite.

Partridge Pea in flower with seed pods. — Partridge Pea with flowers and seed pods in the susquehannawildlife.net garden. Smaller than the other Senna species, Partridge Pea reaches a height of just two to three feet.

August 10, 2023August 14, 2023

Butterflies and More at Boyd Big Tree Preserve Conservation Area

If you’re feeling the need to see summertime butterflies and their numbers just don’t seem to be what they used to be in your garden, then plan an afternoon visit to the Boyd Big Tree Preserve along Fishing Creek Valley Road (PA 443) just east of U.S. 22/322 and the Susquehanna River north of Harrisburg. The Pennsylvania Department of Conservation and Natural Resources manages the park’s 1,025 acres mostly as forested land with more than ten miles of trails. While located predominately on the north slope of Blue Mountain, a portion of the preserve straddles the crest of the ridge to include the upper reaches of the southern exposure.

American Chestnut at Boyd Big Tree Preserve — A grove of American Chestnuts (Castanea dentata) planted at Boyd Big Tree Preserve is part of a propagation program working to restore blight-resistant trees to Pennsylvania and other areas of their former range which included the Appalachians and the upper Ohio River watershed.

Fortunately, one need not take a strenuous hike up Blue Mountain to observe butterflies. Open space along the park’s quarter-mile-long entrance road is maintained as a rolling meadow of wildflowers and cool-season grasses that provide nectar for adult butterflies and host plants for their larvae.

Butterfly Meadow at Boyd Big Tree Preserve — A view looking north at the butterfly meadow and entrance road at Boyd Big Tree Preserve Conservation Area. Second Mountain is in the background.

Walking a Meadow Path — Mowed paths follow the entrance road and a portion of the perimeter of the meadow allowing visitors a chance to wander among the waist-high growth to see butterflies, birds, and blooming plants at close range without trampling the vegetation or risking exposure to ticks.

A Silver-spotted Skipper feeding on nectar from Dogbane (Apocynum cannabinum) flowers. — A Silver-spotted Skipper feeding on nectar from the flowers of Indian Hemp (Apocynum cannabinum). Like the milkweeds, Indian Hemp is a member of the dogbane family (Apocynaceae).

An Eastern Tiger Swallowtail feeding on Common Milkweed.

Great Spangled Fritillary on Common Milkweed. — A Great Spangled Fritillary (Speyeria cybele) on Common Milkweed.

A Black Swallowtail feeding on Common Milkweed nectar. — A Black Swallowtail (Papilio polyxenes) feeding on Common Milkweed nectar.

A Pipevine Swallowtail on Common Milkweed. — A Pipevine Swallowtail (Battus philenor) on Common Milkweed.

A Pipevine Swallowtail on visiting Butterfly Weed. — A Pipevine Swallowtail visiting the brilliant blooms of Butterfly Weed, a favorite of a wide variety of pollinators.

A Black Swallowtail on Butterfly Weed — A Black Swallowtail with damaged wings alights atop a Butterfly Weed flower cluster. Note the pair of parallel rows of red-orange spot on the underside of the hindwing.

A Monarch on Butterfly Weed — A Monarch feeding on nectar from the flowers of Butterfly Weed.

A mating pair of Eastern Tailed Blues. — A mating pair of Eastern Tailed Blues on a Timothy (Phleum pratense) spike.

A female (left) and male Great Spangled Fritillary. — A male Great Spangled Fritillary (right) pursuing a female.

Butterflies aren’t the only colorful insects patrolling the meadows at Boyd Big Tree Preserve. Dragonflies including Common Green Darners are busily pursuing prey, particularly small flying insects like mosquitos, gnats, and flies.

Juvenile Broad-winged Hawk — Dragonflies themselves can become prey and are much sought after by Broad-winged Hawks. This very vocal juvenile gave us several good looks as it ventured from the forest into the skies above the upper meadow during midday. It wasn’t yet a good enough flier to snag a dragonfly, but it will have plenty of opportunities for practice during its upcoming fall migration which, for these Neotropical raptors, will get underway later this month.

Do yourself a favor and take a trip to the Boyd Big Tree Preserve Conservation Area. Who knows? It might actually inspire you to convert that lawn or other mowed space into much-needed butterfly/pollinator habitat.

While you’re out, you can identify your sightings using our photographic guide—Butterflies of the Lower Susquehanna River Watershed—by clicking the “Butterflies” tab at the top this page. And while you’re at it, you can brush up on your hawk identification skills ahead of the upcoming migration by clicking the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab. Therein you’ll find a listing and descriptions of hawk watch locations in and around the lower Susquehanna region. Plan to visit one or more this autumn!

June 18, 2023June 18, 2023

A Few Plants with Wildlife Impact in June

Here’s a look at some native plants you can grow in your garden to really help wildlife in late spring and early summer.

The Larger Blue Flag (Iris versicolor) and Soft Rush (Juncus effusus) in flower in mid-June. — The showy bloom of a Larger Blue Flag (Iris versicolor) and the drooping inflorescence of Soft Rush (Juncus effusus). These plants favor moist soils in wetlands and damp meadows where they form essential cover and feeding areas for insects, amphibians, and marsh birds. Each is an excellent choice for helping to absorb nutrients in a rain garden or stream-side planting. They do well in wet soil or shallow water along the edges of garden ponds too.

The fruits of Smooth Shadbush (Amelanchier laevis), also known as Allegheny Serviceberry, Smooth Serviceberry, or Smooth Juneberry, ripen in mid-June and are an irresistible treat for catbirds, robins, bluebirds, mockingbirds, and roving flocks of Cedar Waxwings.

Common Milkweed and Eastern Carpenter Bee — Also in mid-June, the fragrant blooms of Common Milkweed attract pollinators like Eastern Carpenter Bees,…

Common Milkweed and Honey Bee — …Honey Bees,…

Common Milkweed and Banded Hairstreak — …and butterflies including the Banded Hairstreak (Satyrium calanus). In coming weeks, Monarch butterflies will find these Common Milkweed plants and begin laying their eggs on the leaves. You can lend them a hand by planting milkweed species (Asclepias) in your garden. Then watch the show as the eggs hatch and the caterpillars begin devouring the foliage. Soon, they’ll pupate and, if you’re lucky, you’ll be able to watch an adult Monarch emerge from a chrysalis!

March 3, 2023August 14, 2023

Plantings for Wet Lowlands

This linear grove of mature trees, many of them nearly one hundred years old, is a planting of native White Oaks (Quercus alba) and Swamp White Oaks (Quercus bicolor).

Imagine the benefit of trees like this along that section of stream you’re mowing or grazing right now. The Swamp White Oak in particular thrives in wet soils and is available now for just a couple of bucks per tree from several of the lower Susquehanna’s County Conservation District Tree Sales. These and other trees and shrubs planted along creeks and rivers to create a riparian buffer help reduce sediment and nutrient pollution. In addition, these vegetated borders protect against soil erosion, they provide shade to otherwise sun-scorched waters, and they provide essential wildlife habitat. What’s not to love?

The following native species make great companions for Swamp White Oaks in a lowland setting and are available at bargain prices from one or more of the County Conservation District Tree Sales now underway…

The Red Maple is an ideal tree for a stream buffer project. They do so well that you should limit them to 10% or less of the plants in your project so that they don’t overwhelm slower-growing species.

The River Birch (Betula nigra) is a multi-trunked tree of lowlands. Large specimens with arching trunks help shade waterways and provide a source of falling insects for surface-feeding fish. Its peeling bark is a distinctive feature.

American Robins feeding on Common Winterberry. — An American Robin feeding on Common Winterberry.

Common Spicebush is a shrub of moist lowland soils. It is the host plant for the Spicebush Swallowtail butterfly and produces small red berries for birds and other wildlife. Plant it widely among taller trees to provide native vegetation in the understory of your forest.

Common Spicebush foliage and berries. — Common Spicebush foliage and berries in the shade beneath a canopy of tall trees.

The Buttonbush is a shrub of wet soils. It produces a round flower cluster, followed by this globular seed cluster.

And don’t forget the Eastern Sycamore, the giant of the lowlands. At maturity, the white-and-tan-colored bark on massive specimens makes them a spectacular sight along stream courses and river shores. Birds ranging from owls, eagles, and herons to smaller species including the Yellow-throated Warbler rely upon them for nesting sites.

Yellow-crowned Night Herons Nesting in an Eastern Sycamore — Yellow-crowned Night Herons, an endangered species in Pennsylvania, nesting in an Eastern Sycamore.

So don’t mow, do something positive and plant a buffer!

Act now to order your plants because deadlines are approaching fast. For links to the County Conservation District Tree Sales in the Lower Susquehanna River Watershed, see our February 18th post.

February 23, 2023February 24, 2023

These Geese are Outta Here!

Flies? Cabbage White butterflies? Can it really be a late-February day? It certainly is. Here are a few more signs of an early spring.

Green Frogs were out and about on this balmy February day trying to latch on to one of those flying insects. Their long winter’s nap lasted just over six weeks.

Approximately two hundred Common Grackles passed by susquehannawildlife.net headquarters today. This one stopped to have a look around before continuing its northbound expedition.

Migrating Canada Geese — Difficult to spot, hundreds of high-flying Canada Geese were seen in the hazy sky above the headquarters garden during the late morning. These migrants are working their way north from Chesapeake Bay and won’t be seen again in our region until fall.

February 18, 2023February 22, 2024

Time to Order Your Trees for Spring Planting

County Conservation District Tree Sales are underway throughout the Lower Susquehanna River Watershed. Now is the time to order for pickup in April. The prices are a bargain and the selection is fabulous. For species descriptions and more details, visit each tree sale web page (click the sale name highlighted in blue). And don’t forget to order bundles of evergreens for planting in mixed clumps and groves to provide winter shelter and summertime nesting sites for our local birds. They’re only $12.00 for a bundle of 10—can’t beat that deal!

Cumberland County Conservation District Annual Tree Seedling Sale—

Orders due by: Friday, March 24, 2023

Pickup on: Thursday, April 20, 2023 or Friday, April 21, 2023

Showy Northeast Meadow Mix — Don’t mow it. Plant a meadow or pollinator garden instead.

Dauphin County Conservation District Seedling Sale—

Orders due by: Monday, March 20, 2023

Pickup on: Thursday, April 20, 2023 or Friday, April 21, 2023

American Goldfinch atop an Eastern Hemlock — The Eastern Hemlock, Pennsylvania’s official state tree, is an excellent choice for addition to your landscape or reforestation project. It tolerates rocky soils and its cones are an prime source of food for birds ranging from chickadees to finches.

Lancaster County Annual Tree Seedling Sale—

Orders due by: Friday, March 10, 2023

Pickup on: Thursday, April 13, 2023

The handsome yet underused Northern Red Oak is a sturdy long-lived native tree that is ideal for street-side, lawn, and reforestation plantings. In spring, it can be a magnet for migrating Neotropical birds when its flowers attract a wide variety of tiny insects to its upper reaches. Unlike many other oaks, this species is a relatively fast grower.

Lebanon County Conservation District Tree and Plant Sale—

Orders due by: Wednesday, March 8, 2023

Pickup on: Friday, April 7, 2023

Pileated Woodpecker feeding on Black Gum berries. — In autumn, even after the bright red foliage is gone, the berries of mature Black Gum (Nyssa sylvatica) trees attract a wide variety of birds like this Pileated Woodpecker. The Lebanon County Conservation District is offering Black Gum, also known as Black Tupelo, during their 2023 tree sale. Why not order and plant a half dozen or more?

Perry County Conservation District Tree Sale—(click on 2023 Tree Sale Brochure tab when it scrolls across the page)

Orders due by: March 22, 2023

Pickup on: Thursday, April 13, 2023

Female Eastern Bluebird with Food for Young — The Perry County Conservation District is not only offering plants during this year’s sale, you can also purchase bluebird nest boxes for just $12.00 each!

Riparian Buffer at 15 Years — For less than the cost of one year of mowing, this stream corridor in Conewago Township, Dauphin County was reforested by the owner with hundreds of native trees, the majority purchased through County Conservation District Tree Sale events spanning a period of several years. By replacing bare soil and mowed areas, the riparian buffer created by these plantings has significantly reduced the nutrient and sediment loads that were polluting the small stream therein known as Brill’s Run. With determination and not a lot of money, you can do it too.

Maples, Pin Oaks, Eastern White Pines, and other trees in the Brill's Run riparian buffer. — But don’t forget the Eastern White Pines!

November 10, 2022November 10, 2022

Photo of the Day

The frosted wing edges let you know that this is the winter form of the Eastern Comma butterfly. Adult commas, also known as anglewings, will soon enter crevices in dead and living trees to begin hibernation. On some occasions, they’ll seek shelter from the cold among voids in man-made structures. Look for commas on mild winter days when they awaken to zip around sunny woodlands and gardens. You may even see these speedy little fliers pausing to feed on tree sap or carrion.

October 21, 2022October 22, 2022

Photo of the Day

After somehow finding refuge from freezing temperatures during recent nights, Monarch butterflies were on the move in the Lower Susquehanna River Watershed this afternoon. This one was photographed taking a break to recharge on nectar from flowering Frost Aster, also known as Heath Aster.

October 13, 2022October 13, 2022

Photo of the Day

Hickory Tussock Moth Caterpillar — During autumn, fuzzy caterpillars crossing roads and trails are a familiar sight throughout the Lower Susquehanna River Watershed. In oak-hickory forests you may encounter the stunningly beautiful Hickory Tussock Moth (Lophocampa caryae) caterpillar, but don’t touch it; the spine-like bristles are mildly venomous. Some people react with skin irritation and rashes after contact. This native species rarely defoliates its host trees. When it does, it’s usually just weeks before the deciduous leaves would fall, so the overall health of the plant is little affected. To balance the population, there are numerous avian and terrestrial predators that feed upon both the larval and adult stages of the Hickory Tussock Moth.

October 7, 2022October 8, 2022

Photo of the Day

Butterflies of the Lower Susquehanna River Watershed: Horace's Duskywing — A small butterfly with flights extending into October, the Horace’s Duskywing (Erynnis horatius) is an easily overlooked inhabitant of forest clearings in the vicinity of oaks, particularly Chinkapin Oak (Quercus muehlenbergii), a favorite larval foodplant.

August 20, 2022

Photo of the Day

Zabulon Skipper on Pickerelweed — A female Zabulon Skipper visits a cluster of Pickerelweed blossoms. The Zabulon Skipper is a small butterfly of our streamsides, riversides, damp meadows, and other moist grassy spaces. The Pickerelweed is an emergent plant of lakes, ponds, and wetlands. Add it to your next project to improve water quality and help pollinators like the Zabulon Skipper. You may even attract a hummingbird or two!

July 29, 2022May 20, 2024

Monarch an Endangered Species: What You Can Do Right Now

This month, the International Union for Conservation of Nature (I.U.C.N.) added the Migratory Monarch Butterfly (Danaus plexippus plexippus) to its “Red List of Threatened Species”, classifying it as endangered. Perhaps there is no better time than the present to have a look at the virtues of replacing areas of mowed and manicured grass with a wildflower garden or meadow that provides essential breeding and feeding habitat for Monarchs and hundreds of other species of animals.

Monarch on Common Milkweed Flower Cluster — A recently arrived Monarch visits a cluster of fragrant Common Milkweed flowers in the garden at the susquehannawildlife.net headquarters. Milkweeds included among a wide variety of plants in a garden or meadow habitat can help local populations of Monarchs increase their numbers before the autumn flights to wintering grounds commence in the fall. Female Monarchs lay their eggs on milkweed leaves, then, after hatching, the larvae (caterpillars) feed on them before pupating.

If you’re not quite sure about finally breaking the ties that bind you to the cult of lawn manicuring, then compare the attributes of a parcel maintained as mowed grass with those of a space planted as a wildflower garden or meadow. In our example we’ve mixed native warm season grasses with the wildflowers and thrown in a couple of Eastern Red Cedars to create a more authentic early successional habitat.

Comparison of Mowed Grass to Wildflower Meadow — * Particularly when native warm-season grasses are included (root depth 6′-8′)

Still not ready to take the leap. Think about this: once established, the wildflower planting can be maintained without the use of herbicides or insecticides. There’ll be no pesticide residues leaching into the soil or running off during downpours. Yes friends, it doesn’t matter whether you’re using a private well or a community system, a wildflower meadow is an asset to your water supply. Not only is it free of man-made chemicals, but it also provides stormwater retention to recharge the aquifer by holding precipitation on site and guiding it into the ground. Mowed grass on the other hand, particularly when situated on steep slopes or when the ground is frozen or dry, does little to stop or slow the sheet runoff that floods and pollutes streams during heavy rains.

What if I told you that for less than fifty bucks, you could start a wildflower garden covering 1,000 square feet of space? That’s a nice plot 25′ x 40′ or a strip 10′ wide and 100′ long along a driveway, field margin, roadside, property line, swale, or stream. All you need to do is cast seed evenly across bare soil in a sunny location and you’ll soon have a spectacular wildflower garden. Here at the susquehannawildllife.net headquarters we don’t have that much space, so we just cast the seed along the margins of the driveway and around established trees and shrubs. Look what we get for pennies a plant…

Here’s a closer look…

Lance-leaved Coreopsis (Coreopsis lanceolata), a perennial.

Black-eyed Susan, a biennial or short-lived perennial.

Black-eyed Susan "Gloriosa Daisy" — “Gloriosa Daisy”, a variety of Black-eyed Susan, a biennial or short-lived perennial.

A short variety of Common Sunflower, an annual and a source of free bird seed.

All this and best of all, we never need to mow.

Around the garden, we’ve used a northeast wildflower mix from American Meadows. It’s a blend of annuals and perennials that’s easy to grow. On their website, you’ll find seeds for individual species as well as mixes and instructions for planting and maintaining your wildflower garden. They even have a mix specifically formulated for hummingbirds and butterflies.

Annuals in bloom — When planted in spring and early summer, annuals included in a wildflower mix will provide vibrant color during the first year. Many varieties will self-seed to supplement the display provided by biennials and perennials in subsequent years.

Wildflower Seed Mix — A northeast wildflower mix from American Meadows. There are no fillers. One pound of pure live seed easily plants 1,000 square feet.

Nothing does more to promote the spread and abundance of non-native plants, including invasive species, than repetitive mowing. One of the big advantages of planting a wildflower garden or meadow is the opportunity to promote the growth of a community of diverse native plants on your property. A single mowing is done only during the dormant season to reseed annuals and to maintain the meadow in an early successional stage—preventing reversion to forest.

For wildflower mixes containing native species, including ecotypes from locations in and near the Lower Susquehanna River Watershed, nobody beats Ernst Conservation Seeds of Meadville, Pennsylvania. Their selection of grass and wildflower seed mixes could keep you planting new projects for a lifetime. They craft blends for specific regions, states, physiographic provinces, habitats, soils, and uses. Check out these examples of some of the scores of mixes offered at Ernst Conservation Seeds…

- - Pipeline Mixes
  - Pasture, Grazing, and Hay Mixes
  - Cover Crops
  - Pondside Mixes
  - Warm-season Grass Mixes
  - Retention Basin Mixes
  - Wildlife Mixes
  - Pollinator Mixes
  - Wetland Mixes
  - Floodplain and Riparian Buffer Mixes
  - Rain Garden Mixes
  - Steep Slope Mixes
  - Solar Farm Mixes
  - Strip Mine Reclamation Mixes

We’ve used their “Showy Northeast Native Wildflower and Grass Mix” on streambank renewal projects with great success. For Monarchs, we really recommend the “Butterfly and Hummingbird Garden Mix”. It includes many of the species pictured above plus “Fort Indiantown Gap” Little Bluestem, a warm-season grass native to Lebanon County, Pennsylvania, and milkweeds (Asclepias), which are not included in their northeast native wildflower blends. More than a dozen of the flowers and grasses currently included in this mix are derived from Pennsylvania ecotypes, so you can expect them to thrive in the Lower Susquehanna River Watershed.

Swamp Milkweed, a perennial species, is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”. It is a favorite of female Monarchs seeking a location to deposit eggs.

Monarch Caterpillar feeding on Swamp Milkweed — A Monarch larva (caterpillar) feeding on Swamp Milkweed.

Butterfly Weed (Asclepias tuberosa) is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”. This perennial is also known as Butterfly Milkweed.

Tiger Swallowtails visiting Butterfly Weed — Eastern Tiger Swallowtails are among the dozens of species of pollinators that will visit Butterfly Weed.

In addition to the milkweeds, you’ll find these attractive plants included in Ernst Conservation Seed’s “Butterfly and Hummingbird Garden Mix”, as well as in some of their other blends.

The perennial Wild Bergamot, also known as Bee Balm, is an excellent pollinator plant, and the tubular flowers are a favorite of hummingbirds.

Oxeye is adorned with showy clusters of sunflower-like blooms in mid-summer. It is a perennial plant.

Plains Coreopsis (Coreopsis tinctoria), also known as Plains Tickseed, is a versatile annual that can survive occasional flooding as well as drought.

Gray-headed Coneflower (Ratibida pinnata), a tall perennial, is spectacular during its long flowering season.

Monarch on goldenrod. — Goldenrods are a favorite nectar plant for migrating Monarchs in autumn. They seldom need to be sown into a wildflower garden; the seeds of local species usually arrive on the wind. They are included in the “Butterfly and Hummingbird Garden Mix” from Ernst Conservation Seeds in low dose, just in case the wind doesn’t bring anything your way.

Why not give the Monarchs and other wildlife living around you a little help? Plant a wildflower garden or meadow. It’s so easy, a child can do it.

Planting a riparian buffer with wildflowers and warm-season grasses — Volunteers sow a riparian buffer on a recontoured stream bank using wildflower and warm-season grass seed blended uniformly with sand. By casting the sand/seed mixture evenly over the planting site, participants can visually assure that seed has been distributed according to the space calculations.

Riparian Buffer of wildflowers — The same seeded site less than four months later.

Monarch Pupa — A Monarch pupa from which the adult butterfly will emerge.

October 2, 2021August 15, 2022

Photo of the Day

A migrating Monarch butterfly takes a break to feed on nectar from the blooms of a Frost Aster (Symphyotrichum pilosum), a common autumn wildflower also known as Heath Aster.

March 23, 2021August 15, 2022

Forest vs. Woodlot

Let’s take a quiet stroll through the forest to have a look around. The spring awakening is underway and it’s a marvelous thing to behold. You may think it a bit odd, but during this walk we’re not going to spend all of our time gazing up into the trees. Instead, we’re going to investigate the happenings at ground level—life on the forest floor.

Rotting logs and leaf litter create the moisture retaining detritus in which mesic forest plants grow and thrive. Note the presence of mosses and a vernal pool in this damp section of forest.

The earliest green leaves in the forest are often those of the Skunk Cabbage (Simplocarpus foetidus). This member of the arum family gets a head start by growing in the warm waters of a spring seep or in a stream-fed wetland. Like many native wildflowers of the forest, Skunk Cabbage takes advantage of early-springtime sun to flower and grow prior to the time in late April when deciduous trees grow foliage and cast shade beneath their canopy.

Among the bark of dead and downed trees, the Mourning Cloak butterfly (Nymphalis antiopa) hibernates for the winter. It emerges to alight on sun-drenched surfaces in late winter and early spring.

Another hibernating forest butterfly that emerges on sunny early-spring days is the Eastern Comma (Polygonia comma), also known as the Hop Merchant.

In a small forest brook, a water strider (Gerridae) chases its shadow using the surface tension of the water to provide buoyancy. Forests are essential for the protection of headwaters areas where our streams get their start.

Often flooded only in the springtime, fish-free pools of water known as vernal ponds are essential breeding habitat for many forest-dwelling amphibians. Unfortunately, these ephemeral wetland sites often fall prey to collecting, dumping, filling, and vandalism by motorized and non-motorized off-roaders, sometimes resulting in the elimination of the populations of frogs, toads, and salamanders that use them.

Wood Frogs (Lithobates sylvaticus) emerge from hiding places among downed timber and leaf litter to journey to a nearby vernal pond where they begin calling still more Wood Frogs to the breeding site.

Wood Frog eggs must hatch and tadpoles must transform into terrestrial frogs before the pond dries up in the summertime. It’s a risky means of reproduction, but it effectively evades the enormous appetites of fish.

When the egg laying is complete, adult Wood Frogs return to the forest and are seldom seen during the rest of the year.

In early spring, Painted Turtles emerge from hideouts in larger forest pools, particularly those in wooded swamps, to bask in sunny locations.

Dead standing trees, often called snags, are essential habitats for many species of forest wildlife. There is an entire biological process, a micro-ecosystem, involved in the decay of a dead tree. It includes fungi, bacteria, and various invertebrate animals that reduce wood into the detritus that nourishes and hydrates new forest growth.

Birds like this Red-headed Woodpecker feed on insects found in large snags and nest almost exclusively in them. Many species of wildlife rely on dead trees, both standing and fallen, during all or part of their lives.

There certainly is more to a forest than the living trees. If you’re hiking through a grove of timber getting snared in a maze of prickly Multiflora Rose (Rosa multiflora) and seeing little else but maybe a wild ungulate or two, then you’re in a has-been forest. Logging, firewood collection, fragmentation, and other man-made disturbances inside and near forests take a collective toll on their composition, eventually turning them to mere woodlots. Go enjoy the forests of the lower Susquehanna valley while you still can. And remember to do it gently; we’re losing quality as well as quantity right now—so tread softly.

The White-tailed Deity in a woodlot infested by invasive tangles of Multiflora Rose.

October 5, 2020October 5, 2020

A Visit to Rocky Ridge

Early October is prime time for hawk watching, particularly if you want to have the chance to see the maximum variety of migratory species. In coming days, a few Broad-winged Hawks and Ospreys will still be trickling through while numbers of Sharp-shinned Hawks, Cooper’s Hawks, Northern Harriers, and falcons swell to reach their seasonal peak. Numbers of migrating Red-tailed and Red-shouldered Hawks are increasing during this time and late-season specialties including Golden Eagles can certainly make a surprise early visit.

If you enjoy the outdoors and live in the southernmost portion of the lower Susquehanna valley, Rocky Ridge County Park in the Hellam Hills just northwest of York, Pennsylvania, is a must see. The park consists of oak forest and is owned and managed by the York County Parks Department. It features an official hawk watch site staffed by volunteers and park naturalists. Have a look.

The hawk watch lookout is reached by following the well-marked trail at the north side of the large gravel parking area in the utility right-of-way at the end of the park entrance road (Deininger Road).

The Rocky Ridge Hawk Watch lookout includes outcrops of bedrock, a viewing deck, and grassy areas suitable for lawn chairs.

The bedrock at the lookout is an unusual quartz-cemented conglomerate that forms the Hellam Member at the base of the Cambrian Chickies Formation.

Experienced hawk watchers conduct an official count of raptors and other birds during the autumn migration in September and October each year. Visitors are welcome. The view is spectacular. Check out the concrete columns glowing in the sun to the north of the lookout.

It’s the cooling towers at the Three Mile Island Nuclear Station and the smoke stacks at the Brunner Island Steam Generating Station. Conewago Falls is located between the two.

Interpretive signage on the hawk watch deck includes raptor identification charts.

A migrating Osprey glides by the lookout.

Throughout the month, migrating Sharp-shinned Hawks will be flying in a southwesterly direction along ridges in the region, particularly on breezy days. They are the most numerous raptor at hawk watches in the lower Susquehanna valley during the first half of October.

A Peregrine Falcon quickly passes the Rocky Ridge lookout. These strong fliers often ignore the benefits provided by thermals and updrafts along our ridges and instead take a direct north to south route during migration.

And a little while later, an adult Red-tailed Hawk follows.

Bald Eagles, including both migratory and resident birds, are seen regularly from the Rocky Ridge lookout.

Other diurnal (daytime) migrants are counted at Rocky Ridge and some of the other regional hawk watches. Massive flights of Blue Jays have been working their way through the lower Susquehanna valley for more than a week now. Local hawk watches are often logging hundreds in a single day.

The utility right-of-way within which the Rocky Ridge Hawk Watch is located can be a great place to see nocturnal (nighttime) migrants while they rest and feed during the day. Right now, Eastern Towhees are common there.

An uncommon sight, a shy Lincoln’s Sparrow (Melospiza lincolnii) in the utility right-of-way near the hawk watch lookout. This and other nocturnal migrants will take full advantage of a clear moonlit night to continue their southbound journey.

If you’re a nature photographer, you might be interested to know that there are still hundreds of active butterflies in Rocky Ridge’s utility right-of-way. Here are a few.

To see the daily totals for the raptor count at Rocky Ridge Hawk Watch and other hawk watches in North America, and to learn more about each site, be certain to visit hawkcount.org

September 15, 2020September 16, 2020

Fire and Ice at Conewago Falls

This morning, the Lower Susquehanna River Watershed experienced remotely the effects of fire and ice.

At daybreak, the cold air mass that brought the first freeze of the season to northernmost New England gave us a taste of the cold with temperatures below 50 degrees throughout.

The air temperature at daybreak in the Gettysburg Basin east of Conewago Falls.

At sunrise, the cloudless sky had a peculiar overcast look with no warm glow on buildings, vegetation, and terrain. Soon, the sun was well above the horizon, yet there was still a sort of darkness across the landscape.

Smoke from massive wildland fires in the Pacific Coast States created a haze that persisted throughout the day in the Susquehanna valley.

Away from traffic and the odors of agriculture and urban life, the smell of wood smoke was easily detectable. The haze from fires almost 3,000 miles away made it appear to be an overcast day at Conewago Falls.

Due to the sudden cold, there were no insects flying above the Susquehanna during the first hour of daylight this morning, so swallows gathered in the trees to conserve energy until the hunt would be more productive.

The diabase boulders at Conewago Falls retain heat and provide an even better refuge from the cold than a dead tree on a chilly morning. Here, a juvenile and an adult Tree Swallow (center) are surrounded by Northern Rough-winged Swallows. Hundreds of each of these migratory species were feeding at the falls today.

Two dozen or more Barn Swallows, including this juvenile, were seen among the swarming birds.

Several late Bank Swallows, including this one (bottom center), were among the flocks of migrants at Conewago Falls this morning. One Cliff Swallow (Petrochelidon pyrrhonota) was seen as well.

A Great Egret (Ardea alba) and a Great Blue Heron.

An Osprey searching the clear pools and rapids for a morning meal.

A juvenile Bald Eagle with the same goal in mind.

The same Bald Eagle keeping a close watch on the Osprey. Bald Eagles frequently ambush Ospreys to steal their catch. For a young eagle, acquiring the skill of fish theft may improve its chances of survival, at least until the Ospreys head south.

All that bright filtered sunlight was ideal for photographing butterflies along the Conewago Falls shoreline. Have a look.

During the late morning, dozens of Monarch butterflies migrated past Conewago Falls. This one paused to feed.

The Viceroy (Limenitis archippus) is a Monarch mimic. Its appearance fools would-be predators into thinking it is a Monarch and possesses the same foul flavor as the milkweed-raised model.

This Variegated Fritillary (Euptoieta claudia) was among the late-season butterflies at Conewago Falls.

The Common Buckeye is presently just that, very common on flowers and moist sandy soil around the falls.

The Painted Lady is a regularly-occurring migratory species of butterfly.

The Red Admiral is typically a common to abundant migrant. So far in 2020, they are scarce in the lower Susquehanna valley.

August 25, 2020August 21, 2023

Stray Butterflies

A special message from your local Chinese Mantis (Tenodera sinensis).

Hey you! Yes, you. I pray you’re paying attention to what’s flying around out there, otherwise it’ll all pass you by.

This summer’s hot humid breezes from the south have not only carried swarms of dragonflies into the lower Susquehanna valley, but butterflies too.

So check out these extravagant visitors from south of the Mason-Dixon Line—before my appetite gets the better of me.

In some years, the Sachem, a vagrant from the south, can become the most frequently observed orange skipper in the Susquehanna valley, far outnumbering faltering populations of resident species around lawns, gardens, meadows, and roadsides. 2020 appears to be one of those years.

The Fiery Skipper (Hylephila phyleus) sometimes strays north along the lower Susquehanna River in late summer. This one was photographed recently at Conewago Falls.

The Cloudless Sulphur is a large fast-flying brilliant yellow butterfly. Here in the Susquehanna valley, it is usually seen singly, though colonizers will breed in patches of Partridge Pea, Wild Senna (Senna hebecarpa), and Maryland Senna (Senna marilandica). Cloudless Sulphurs are really widespread this year. In areas where intensive farming practices are in use, your chances of seeing one of these wandering around right now might be just as good as your chances of seeing one of the diminished flights of the resident Clouded Sulphurs (Colias philodice) and Orange Sulphurs (Colias eurytheme).

The Red-banded Hairstreak (Calycopis cecrops) is the least conspicuous of the stray butterflies shown here. This beauty was photographed several days ago along the edge of an oak forest in northern Lancaster County, PA.

There you have it. Get out there and have a look around. These species won’t be active much longer. In just a matter of weeks, our migratory butterflies, including Monarchs, will be heading south and our visiting strays will either follow their lead or risk succumbing to frosty weather.

For more photographs of butterflies, be sure to click the “Butterflies” tab at the top of the page. We’re adding more as we get them.

Category: Butterflies and Moths (Lepidoptera)

Photo of the Day

Photo of the Day

Soakin’ Up the Smoky Sun

Late May Action in the Forest

Back in the Day: Down on the Farm

Six Flowering Woody Plants

Things to See While You’re Leaf Peeping

A Prescribed Fire Site After the Burn

Aphrodite Fritillary

Wildflower Meadow Update

Arboreal Birds and Tent Caterpillars

Prescribed Fire: Controlled Burns for Forest and Non-forest Habitats

Time to Order Trees and Shrubs for Spring

Photo of the Day

The Gray Comma: Now You See Me, Now You Don’t

A Visit to a Beaver Pond

Wild Senna, a Showy Background Plant for Your Wildflower Garden

Butterflies and More at Boyd Big Tree Preserve Conservation Area

A Few Plants with Wildlife Impact in June

Plantings for Wet Lowlands

These Geese are Outta Here!

Time to Order Your Trees for Spring Planting

Photo of the Day

Photo of the Day

Photo of the Day

Photo of the Day

Photo of the Day

Monarch an Endangered Species: What You Can Do Right Now

Photo of the Day

Forest vs. Woodlot

A Visit to Rocky Ridge

Fire and Ice at Conewago Falls

Stray Butterflies